Hi there! Hopefully this helps!
---------------------------------------------------------------------------------------------
If it were me, I would tell her that if her prediction is accurate, the chance of getting tails is 0.5 (Since 240 is half of 480). The odds of landing heads would be identical, 0.5. In real life, she wouldn't certainly get 240 tails out of 480 tosses, but the standard rate of the number of tails would certainly be resembling 0.5.